The Vatican has detailed laws and rituals to ensure the transfer of power when a pope dies or resigns, but not when he is sick.

What happens when a pope is incapacitated? Is he still pope? Pope Francis' age and prolonged illness have raised questions about whether he might resign, and revived interest about how papal power is exercised.

The Bishop of Rome, Pope Francis is currently hospitalized due to double pneumonia also known as bilateral pneumonia that affects the lungs. According to the Vatican, Pope was admitted to the Agostino Gemelli Polyclinic for diagnostic tests and treatment for bronchitis.

Pope Francis rested overnight in the hospital, the Vatican said earlier Sunday, adding that his night "passed peacefully."

“Pope Francis is touched by the numerous messages of affection and closeness that he continues to receive in these hours,” the Vatican statement said. The pope expressed particular gratitude for the well wishes he received from his fellow patients in Rome’s Gemelli Hospital and asked for continued prayers.